SCADA (was Re: Help to identify a computer?)

On 17 Feb 2007 at 19:38, Tim Shoppa wrote: It's too bad that no one seems to make a hobby out of collecting old process-control equipment. I helped get me through college by working as an instrumentation technician summers. Really primitive stuff--your basic tools were a portable potentiometer, optical pyrometer and your pocket thermometer--and a pen-cleaning wire. A lot of the stuff was probably from the 20's. L&N Micromax chart recorders/controllers (used a clockspring motor to run the works; basically an automatic clamp galvanometer in a wheatstone bridge), Askania hydraulic controls. Some of the more modern stuff was Brown Electronik (later became part of Honeywell), and L&N Speedomax, using mechanical chopper-stabilized amplifiers--and the very newest stuff was Moore pneumatic. The first non-human square root-extractor unit I ever saw was pneumatic (used to compute flow from differential pressure). Very high-tech in those days. Much of the equipment ran as rattle). Steel mills used to generate their own power by burning coke-oven (producer) gas. For some reason never made clear to me, one of the competing "standards" for AC distribution was 25Hz (both 50 and 110v). The most advanced bit of equipment that I saw at that time was used to measure the dewpoint of the hydrogen reducing atmosphere on the continuous hot-galvanize line. A tiny mirror was cooled by a refrigeration unit and a sample of the atmosphere was directed onto its surface. A phototube measured the degree of fogging. Cheers, Chuck